The present invention relates to an air-bag arrangement, and more particularly relates to an air-bag arrangement for use in a motor vehicle in the form of a so-called “inflatable curtain”.
An inflatable curtain is an air-bag or inflatable element which is initially mounted in the roof of a motor vehicle adjacent the side windows of the vehicle. In the event of a specific type of accident, such as, for example, a side impact, the inflatable element inflates, thus extending down to cover the windows in the manner of a curtain. Typically the opposed ends of the lower edge of the inflatable element are secured to mounting points, optionally with the use of straps, and, as the inflatable element inflates, so the length of the lower edge of the inflatable element reduce, thus creating a line of tension extending between the two anchoring points. Thus the inflatable element is held securely in position, minimizing the risk of any part of an occupant emerging through a window during the accident.
It has been proposed to provide certain regions of the inflatable element which do not actually inflate in order to minimize the quantity of gas needed to inflate the inflatable element, and also to ensure that the inflatable element can be inflated in the relatively brief period of time that is typically available in a side impact situation.
While many designs of inflatable curtain have been produced in recent years for use in different types of motor vehicle. It has been found, especially in connection with inflatable elements designed for use in vehicles having a substantial length, such as vehicles of “MPV” type, where the inflatable element can extend from an “A”-Post to a “D”-Post that, excessive tension can occur in parts of the inflatable curtain, thus distorting the inflatable curtain in an undesirable manner.
The present invention seeks to provide an improved air-bag arrangement.
According to this invention there is provided an air-bag in the form of a one-piece woven inflatable curtain, the inflatable curtain defining at least two spaced-apart inflatable regions and an uninflatable region, the uninflatable region incorporating an expansion panel, the expansion panel having two outer fabric layers, the outer fabric layers being interconnected by an intermediate or third layer extending from a first region where it merges with a first of the two outer layers to a second region where it merges with the second of the two outer layers, there being a slit line formed in the first layer between the first region and an adjacent edge of the expansion panel, and there being a further slit line provided in the second layer between the second region and the other edge of the expansion panel.
Preferably there is a second intermediate or third layer extending between the first and second layers of fabric, the second intermediate or third layer extending from a point between the further slit line and the other edge of the expansion panel and a part of the first layer of fabric closer to the other edge of the panel, there being a further slit line formed in the first layer of fabric between the part and the other edge of the panel.
Conveniently wherein the slit line is in the form of an actual slit.
Alternatively the slit line is in the form of a perforated line of slits.
Alternatively wherein the slit line is in the form of a line formed with weak threads configured to rupture when a predetermined tension is applied to them.
Preferably, the uninflatable region is located between and separates two spaced apart inflatable regions.
Alternatively, the uninflatable region is located between one of the inflatable regions and part of the air-bag configured for connection to an anchoring point.
In order that the invention may be more readily understood, and so that further features thereof may be appreciated, the invention will now be described by way of example, with reference to the accompanying drawings in which: